1. Field of the Invention
The present invention relates a teaching method of a transmission control unit (TCU), in detail, a technology for initializing a TCU controlling a transmission equipped in a vehicle.
2. Description of Related Art
In transmission equipped vehicles, a transmission control unit (TCU) that is an electronic controller for controlling transmission that are electronically controlled are equipped in vehicles together with the transmissions.
The transmissions are manufactured in the transmission production line, and after they are completed, various property data of the transmissions is measured by FINAL TESTER in the transmission production line.
On the other hand, the TCUs are manufactured in another TCU production line and are assembled with vehicles in the vehicle assembly line together with the transmissions manufactured as described above.
The TCUs can correctly control the transmissions when the various specific property data of the transmission equipped in the vehicles is inputted, however, since the property data of the transmissions are measured in the transmission production line, it is required to transmit the data measured in the transmission production line to the vehicle assembly line where the transmission and the TUC are equipped in the vehicles and input correct data of corresponding transmissions into TCUs.
It is called ‘teaching’ to input and initialize property data of a transmission to be controlled to a TCU.
A typical method of transmitting specific data of a corresponding transmission which is measured in the transmission production line to the vehicle assembly line where the TCU is equipped in the related art is to input the data measured in the transmission production line to a barcode and attach it to the corresponding transmission, and then scan the barcode in the vehicle assembly line to ensure the data to input to the TCU. However, the barcode is classified into a one-dimensional barcode and a two-dimensional barcode, in which the one-dimensional barcode can transmit a very small amount of data and the two-dimensional barcode can store relatively a large amount of data, such that the two-dimensional barcode is suitable to transmit various property data of transmissions.
However, the two-dimensional barcode is more expensive than the one-dimensional barcode, the scanning device is also relatively expensive, and it is relatively difficult to perform the scanning operation.
On the other hand, in the transmissions, a kiss-point is one of important specific properties of transmissions which are CVT (Continuously Variable Transmission) that is equipped with a wet-type multi-disc clutch therein instead of a torque converter and directly controls the wet-type multi-disc clutch with a solenoid valve.
The kiss-point implies a state in which start-slip control is ready to be started by applying hydraulic pressure to a position where frictional force of the clutch of a wet-type multi-disc clutch starts to be generated, and in detail, hydraulic pressure that generates the power transmission start state is called kiss-point pressure.
In the transmissions having the above structure, the kiss-point pressure changes for each transmission by return spring tolerance, clutch clearance difference, pressure sensor tolerance, solenoid valve tolerance, and leaking oil difference of other sealed portions of the wet-type multi-disc clutch. If the kiss-point pressure is larger than a designed value, the engine may by stopped by excessive clutch pressure in shifting from the N-range to the D-range, and when the kiss-point pressure is smaller than the designed value, the response is delayed when the vehicle starts. Therefore, the kiss-point pressure is a very important specific property of transmissions and also data that should be transmitted and inputted to TCUs.
In the CVT having the above structure, the kiss-point pressure is determined by electric current provided from the solenoid, such that the electric current that should be provided from the solenoid valve to create the kiss-point pressure is called kiss-point electric current.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.